That green-blue is not just green and blue put next to each other but it is green and blue blended together and bending toward each other in ways that may be atypical.
I would agree with this if mathematics didn't already feel like the most blue thing in existence. Green doesn't contribute anything. One of the dichotomies that defines the relationship between green and blue to me is that of wisdom vs. knowledge, and math falls squarely into the latter camp. If I wanted to make an UG school type thing, it would probably be like paleontology, or maybe astrology.
This seems like a personal feel thing, but to me, mathematics seems to be more about discerning what is true by exploring what is possible using rigid preexisting truths.
To me, applied knowledge is a better representation of blue beyond the cliché of the "knowledge for knowledge's sake" theorist, because blue doesn't just care about knowledge but also about mastery and self-determination. Engineering feels much more blue than just theoretical math. Blue takes what is true and builds new things from it, changes itself and the world with it, and ultimately change what is true. The most fanatical blue, to me, would want to ultimately break the physical laws of the universe to go even further. I just watched this series for the first time, so think Rick Sanchez from Rick and Morty.
On the other hand, Daoist philosophy has us understand the world is made up of patterns for which the material reality are simply expressions of more pure truth. Exploring nature through observation and experimentation to better understand how all things are ultimately the same, merely shadows of the unbreakable movement of the universe. I think this is a valid interpretation of mathematics study as a green practice.
Lockhart's Lament actually goes more into how math education falls short of mathematics as a field. He talks about math as an art and how math teaching doesn't capture the aesthetic and intuitive parts of math.
I agree that math as a field is more intellectually rigorous and logic-driven than green is, but that's why Quandrix is green-blue.